This invention relates to a service estimation apparatus for an elevator which calculates a new index for estimating the state of service by the elevator.
It has heretofore been common practice that the number of hall calls, periods of waiting time, etc. are actually measured in a building in which an elevator is operating, to decide from the measured results whether or not the situation of service by the elevator is favorable, whether the service situation is better or worse than in other buildings, and so forth. As is well known, the service state of an elevator, for example, the distribution of periods of waiting time differs greatly depending upon conditions special to a building (such as the purpose, the number of floors, and the heights of floors of the building; the number, the rated speed, and the rated capacity of elevator cages; a group-supervisory system; and traffic volume fluctuating in accordance with time zones). Accordingly, the estimated index of elevator service should desirably be one with which the service states can be readily compared and calculated with each even when the conditions special to buildings are different.
Conventionally speaking, the mean periods of waiting time, the maximum periods of waiting time are the most commonly used estimated indices. As the mean periods of waiting time and the maximum periods of waiting time are shorter and as the rate of occurrence of long waits is smaller, the service is decided better. Recently, however, more importance is attached to the rate of occurrence of long waits (the proportion of hall calls whose periods of waiting time become, for example, at least 60 seconds with respect to all hall calls) than to the mean periods of waiting time in the estimation.
Furthermore, in some applications, the riding period of time (a period of time required for a person to reach a destination floor since getting on a cage), the service completion period of time (a period of time required for the person to reach the destination floor since entering a hall), etc. are utilized in addition to the periods of waiting time of the hall call in the service estimation of the elevator.
Heretofore, various apparatuses for measuring and estimating the state of service by an elevator as described above have been proposed.
Examples of the proposals are an elevator operation data-collecting apparatus described in Japanese Patent Application Publication No. 58-56711, in which the numbers of persons who get on and off elevator cages are automatically collected and are stored in a recording device and in Japanese Patent Application Laid-Open No. 59-163279, in which various data items concerning elevator traffic are measured to calculate the mean periods of waiting time, the rate of occurrence of long waits, the rate of missing of forecasts, etc. as the estimated service indices of the elevator, and when the estimated service index has become worse than a predetermined value in which an alarm is issued on a display unit.
Further, in view of the above-stated fact that importance is attached to the rate of occurrence of long waits as a estimated service index, an operating state measurement apparatus described in Japanese Patent Application Publication No. 51-47017 has proposed that the mean periods of waiting time W.sub.m, the variance of waiting time W.sub.v, and the rate of occurrence of long waits P.sub.r are actually measured, and that on the basis of resuts obtained by analyzing the actually measured data by means of tabulation and a statistic method, the rate of occurrence of long waits whose periods of waiting time are longer than N times the mean periods of waiting time W.sub.m, denoted by P.sub.r (W&gt;N.multidot.W.sub.m), is approximately calculated by the following linear function: ##EQU1## which is used as a service index..
In case of using the rate of occurrence of long waits as the estimative index, however, there have been several problems. Since the system which calculates the rate of occurrence of long waits supply from the proportion of long wait calls occupies among measured hall calls, when the number of the measured hall calls is not sufficient, or when a reference value for deciding the long wait (hereinbelow, termed `long wait reference value`) is set to a value which is excessively great in comparison with a mean value, the calculated rate of occurrence of long waits becomes zero by way of example, resulting in the problem that the quality of service of the concerned elevator cannot be compared with that of another elevator. Meanwhile, with the system which presumes the rate of occurrence of long waits Pr from the aforementioned approximation formula, the long wait reference value is set according to the product N.multidot.Wm between the constant N and the mean periods of waiting time Wm. In this regard, in case of comparing the particular situation of service with those in another time zone and another building, the mean periods of waiting time Wm differ under the respective conditions, and hence, the long wait reference values become diverse. This leads to the problem that the comparisons are difficult with the long wait occurrence rate Pr. In addition, when it is intended to make comparisons by the use of an identical long wait reference value, the constants a and b need to be previously determined for all the values of the constant N. Moreover, since the shape of the distribution of hall calls changes depending also upon the group-supervisory system, the intended purpose of a building, etc., the constants a and b are determined beforehand in relation to these individual factors. This leads to the problem that laborious determination is involved.